Packages

Bevy is a Cargo workspace of ~60 crates, all named bevy_* and all under crates/. The bevy umbrella crate at the workspace root is just a re-export of bevy_internal, which itself depends on most of the others. Most of the time you depend on bevy and toggle features; once you understand the workspace you can also depend on individual bevy_* crates directly.

This section has one page per crate. Pages are concise — they describe purpose, key types, and entry points for modification. Use them as jumping-off points into crates/<name>/src/.

How to read a package page

Each page follows the same structure:

1. Purpose — what the crate does, in 2–3 sentences.
2. Key types — the public surface that matters most.
3. How it works — internal architecture, with diagrams when they help.
4. Integration points — what it depends on and what depends on it.
5. Entry points for modification — where to look first when changing the crate.

Crate map by domain

The 60 official crates organize naturally into a few clusters.

Foundations

Crate	Files	Purpose
bevy_app	13	The App, plugins, schedules, panic and signal handling.
bevy_ecs	154	The Entity Component System.
bevy_reflect	141	Runtime reflection for Rust types.
bevy_internal	3	The DefaultPlugins group; re-exports of all subordinate crates.
bevy_math	46	Vectors, matrices, curves, geometric primitives, easing.
bevy_color	23	Color types and color-space conversions.
bevy_tasks	11	Task pools, async helpers.
bevy_platform	26	Cross-platform shims (time, HashMap, atomics) for no_std.
bevy_utils	9	Small helpers used across the workspace.
bevy_ptr	1	Tiny crate for type-erased pointer helpers.
bevy_derive	4	The #[derive(Deref)], #[derive(DerefMut)], etc. helpers.
bevy_macro_utils	10	Shared utilities used by Bevy's proc macros.
bevy_encase_derive	1	Derive bridge for the encase GPU-buffer encoding crate.
bevy_dylib	1	Dummy crate that re-exports bevy as a .dylib/.so for fast compiles.

Time and lifecycle

Crate	Files	Purpose
bevy_time	9	Frame time, fixed-timestep accumulator, virtual/real clocks.
bevy_diagnostic	7	Time-windowed measurement registry (FPS, entity count, etc).
bevy_state	15	Typed state machines (Menu/Game/Paused).
bevy_log	3	tracing/log integration, panic-hook installer.
bevy_transform	9	Local + global transforms, propagation systems.
bevy_settings	3	User-preference loader/saver.
bevy_a11y	1	AccessKit integration for accessibility.

Assets, scenes, and serialization

Crate	Files	Purpose
bevy_asset	37	Loader, server, processor, hot-reload.
bevy_scene	8	Spawning saved/loaded scenes into a world.
bevy_world_serialization	10	The BSN format, scene save/load.
bevy_gltf	16	glTF 2.0 loader.

Rendering

Crate	Files	Purpose
bevy_render	71	Render SubApp, render graph, GPU resource management.
bevy_core_pipeline	28	Shared 2D/3D core (clear, depth prepass, tonemapping, bloom, MSAA).
bevy_pbr	59	PBR materials, lights, shadows, deferred pipeline.
bevy_camera	9	Camera component, projections, culling primitives.
bevy_camera_controller	3	Free-look / orbit camera helpers for examples.
bevy_mesh	25	Mesh data, attributes, primitive meshing.
bevy_image	15	Image / texture asset types.
bevy_material	9	The Material trait, asset glue.
bevy_light	14	Point, spot, directional lights and clustered shading.
bevy_shader	3	Shader asset types (WGSL/SPIR-V).
bevy_anti_alias	11	FXAA, SMAA, TAA, contrast-adaptive sharpening.
bevy_post_process	18	DOF, bloom, chromatic aberration, motion blur.
bevy_solari	14	Experimental ray-traced GI.
bevy_sprite	8	2D sprite components.
bevy_sprite_render	15	2D sprite renderer.
bevy_gizmos	22	Immediate-mode debug drawing API.
bevy_gizmos_render	5	Renderer for bevy_gizmos.
bevy_text	15	Text shaping, rendering, font assets.

Animation

Crate	Files	Purpose
bevy_animation	9	Skeletal and morph-target animation, animation graph.

Input, windowing, and platform

Crate	Files	Purpose
bevy_window	9	Window component, events, mode types.
bevy_winit	10	winit integration: event loop, swapchain handling.
bevy_input	9	Keyboard, mouse, touch, gamepad button state.
bevy_input_focus	6	Which entity receives keyboard input.
bevy_gilrs	4	gilrs gamepad backend.
bevy_clipboard	1	Clipboard read/write resource.
bevy_android	1	Android-specific platform glue.

UI

Crate	Files	Purpose
bevy_ui	26	UI nodes, flexbox layout via taffy, focus, rendering data.
bevy_ui_render	10	Renderer for UI nodes.
bevy_ui_widgets	10	Composed widget primitives (buttons, sliders, scrollbars).
bevy_feathers	33	Bevy's built-in widget set and theme.

Audio

Crate	Files	Purpose
bevy_audio	7	rodio-based audio playback, spatial audio.

Picking

Crate	Files	Purpose
bevy_picking	10	Picking core: pointers, hits, events.

Tooling and remote inspection

Crate	Files	Purpose
bevy_dev_tools	15	FPS overlay, state inspector, debug helpers.
bevy_remote	6	The Bevy Remote Protocol (BRP) — JSON-RPC over HTTP.

Reading order for new contributors

1. bevy_app — understand App, plugins, schedules.
2. bevy_ecs — the data model.
3. bevy_reflect — runtime reflection.
4. bevy_asset — how assets get into the world.
5. bevy_render — the render SubApp.
6. Then whichever subsystem your task lives in.